low carbon energy and engineering

no such thing as a green office?

Following our recent blog conversation about the energy consumption of Portcullis House, Phil at the Sustainability Blog has pointed out the recently published consumption figures for another Hopkins scheme – this time the Gibbs Building owned by the Wellcome Trust. Like Portcullis House, it’s an office building kitted out with plenty of green gear. And like its cousin, the Gibbs Building is consuming more energy than predicted at design stage. So is the green office building just a myth?

I should point out that the Gibbs Building gets much closer to its initial targets than Portcullis House. Converting energy figures from the Wellcome Trust into CO2, in 2005 the building outperformed its design targets by 1.8% and beat the Econ19 benchmarks by nearly 12%. But in 2006, perhaps because of the spate of hot weather, the building emitted about 13% more carbon than predicted at design stage and only just met the Econ19 benchmarks.

As temperatures in London continue to rise, it’s likely that future energy consumption will resemble 2006 figures more than those of 2005.

So we’ve got a flagship building that’s only just scraping the Econ19 benchmarks. You could argue that this isn’t such a poor performance, but then this is no ordinary prestige office building: double façade, chilled beam cooling, a free cooling strategy at times when external temperatures drop below 10°C, displacement ventilation, fritted glass in the roof of the atrium to reduce solar gain, a solid daylighting strategy, and demand-led controls via the BMS.

In addition, the Econ19 good practice figures reflect the top quartile of office buildings monitored in the 1990’s. So despite a massive tightening of the building regs, we’re still comparing our offices to those built when Vanilla Ice was in the charts and many of us dressed like Eddie Vedder and spoke like Ted Theodore Logan. It’s a time best forgotten. We need a new Econ19 using new offices in order for the benchmarks to be meaningful. And while this idea has been floating around for some time, I don’t think a new version is in the works.

To rant just a bit more, there’s a lot of nifty kit in this building, much of it aimed at compensating for the fact that it’s essentially a glass and steel box – an inefficient form when it comes to maintaining comfortable conditions for occupants. Exactly like a greenhouse, it’s poorly insulated in winter and quickly bakes in summer. So why do it? Vanity? Architectural convention? I’m not sure – but one thing I am sure of is that, while they’ve made a hell of an effort, this isn’t the office of the future.

This is exactly where all the best kit in the world and well thought out strategies cannot compensate for design ineptitude. Ostriches and sand spring to mind. Initial passive-led design is really the only way to address excess energy consumption in new buildings.

Thanks also for a great Lads Camp and good to see the Blog up and drunning again

I knew you’d get stuck into these figures Casey.
Moving things forwards a little – if this isn’t the office of the future, what is? Is there a new architectural style/form that the industry now needs to adopt to get better performing offices? How can we grapple with energy guzzling nature of your typical office?
A few easy starter for ten questions for you.

Fair point Phil. It’s easy to criticise other people’s designs but not so easy to come up with better answers.

I’d say the important issues to address in the passive design are heating, cooling, and daylight. Shallow-ish floorplates with a more reasonable glazing ratio (say 30%) and well insulated walls are a sound start I think. If there is potential for daylighting then it’s down to shading and controls to make the most of it. But it’s a shame to hamstring yourself at the outset by choosing architecture based only on glass and steel.

In the case of the Gibbs Building, the client is also the occupant so they were able to choose better services – chilled beam for example rather than VAV. But if this had been a spec office it would have been much worse. A lot of that is down to the letting agents I think. While occupants might be interested in a more innovative building (and one with windows that open!) there seems to be a wide assumption among developers that letting agents will only take a very narrow spec.